OLIGOCLONAL REPERTOIRE OF THE CD8-ALPHA-ALPHA AND THE CD8-ALPHA-BETA TCR-ALPHA BETA MURINE INTESTINAL INTRAEPITHELIAL T-LYMPHOCYTES - EVIDENCE FOR THE RANDOM EMERGENCE OF T-CELLS/

The epithelium of the small intestine in normal euthymic mice contains a large number of intraepithelial lymphocytes (IEL), some of which be ar a T cell receptor alpha/beta (TCR-alpha/beta). About half of these TCR-alpha/beta IEL display the CD8 alpha alpha phenotype and the remai ning have the CD8 alpha beta or the CD4 phenotypes. To examine whether TCR-alpha/beta IEL have a TCR-beta chain repertoire as diverse as tha t of TCR-alpha/beta lymph node lymphocytes (LNL), we used a recently d escribed PCR technique that allows a global analysis of the TCR-beta c hain repertoire. Within any given mouse, the repertoires expressed in both CD8 alpha alpha and CD8 alpha beta TCR-alpha/beta IEL. population s are oligoclonal and nonoverlapping between the two subsets. The clon es are largely conserved through the length of the small intestine of the same individual. However, genetically identical individuals raised under indistinguishable environmental conditions display distinct oli goclonal repertoires. Those findings indicate that few cells of CD8 al pha alpha or of the CD8 alpha beta phenotype are responsible for the r epopulation of the intestinal epithelium.